A sample aspiration pipe which has a aspiration thin tube for aspirating a sample and a ventilation thin tube for performing a ventilation in a container at the time of aspiration, and punctures the cap by using both the thin tubes has conventionally been known as the sample aspiration pipe for aspirating a liquid sample in a sample container sealed by a cap such as a rubber cap (for example, see Japanese Patent Application Laid-Open (JP-A) No. 58-76765).
The sample aspiration pipe disclosed in Japanese Patent Application Laid-Open (JP-A) No. 58-76765 is a main constituent element of a sample feed device for aspirating and supplying the sample in a seal pipe to an automatic sample inspection device, and have a coaxial structure where two thin tubes are arranged in the same axis. That is, a ventilation thin tube is provided on the same axis as a aspiration thin tube on the outer circumference of the aspiration thin tube having a center passing hole. The sample in a seal pipe is sucked via the center passing hole. On the other hand, the inside of the seal pipe is ventilated with atmosphere via a flow channel between the aspiration thin tube and the ventilation thin tube at the time of aspirating.
However, since the sample aspiration pipe has a structure where two thin tubes are arranged on the same axis, the manufacture is difficult, and thereby the cost is high. Since it is necessary to clean the outer circumferences of two thin tubes, there is a problem in that a cleaning step is complicated.
On the other hand, a sample aspiration/discharging device for piercing a cap by using a aspiration needle to releasing the inside of a container to atmosphere, extracting the aspiration needle from the cap, cleaning the outside and inside of the aspiration needle, and piercing the cap by using the aspiration needle again to suck the liquid sample has been known as a sample aspiration/discharging device for aspirating and discharging the liquid sample in the sample container sealed by the cap using the aspiration needle (for example, see Japanese Patent Application Laid-Open (JP-A) No. 2001-153762).
However, when aspirating small amount of liquid sample while determining the quantity of the liquid sample, there is a problem in that the quantification accuracy for determining the quantity is insufficient in the device described in Japanese Patent Application Laid-Open (JP-A) No. 2001-153762.
The sample aspiration/discharging device holds the sealed container so that the cap is located below, and punctures the cap using the aspiration needle toward the top from the bottom to release to atmosphere. After the sample aspiration/discharging device extracts the aspiration needle from the cap, the sample aspiration/discharging device reverses a aspiration needle, soaks the tip in a cleaning tub to clean the inside of the aspiration needle, and the sample aspiration/discharging device punctures the cap using the aspiration needle again to suck the liquid sample. Thereby, the cleaning device for cleaning the outside of the aspiration pipe and the cleaning tub for cleaning the inside of the aspiration pipe are required, and the device constitution and a sequence for aspirating the liquid sample are complicated.